If we apply DC voltage then as we know Capacitor blocks the flow of DC, only leakage current due to imperfection of insulator will flow and hence the Resistance measured by Megger will actually represent Insulation Resistance. This is the reason, an Insulation Tester or Megger have DC voltage generator.

What voltage is insulation resistance test?

The insulation resistance test is an electrical test which uses a certain type and level of voltage (500V d.c. for low voltage installations i.e.: 230V) to measure insulation resistance in Ohm`s. The measured resistance indicates the condition of the insulation between two conductive parts.

How much voltage does a Megger put out?

Megger testing does not cause any damage, making it a good option when someone does not want to put holes in walls to test electrical insulation for any problems or issues. The testing device only goes between 500 and 1,000 volts, which is relatively low.